JP6222765B2 - Magnetron, filter for magnetron, and method for manufacturing magnetron - Google Patents

Description

  The present invention relates to a magnetron, a filter for a magnetron, and a method for manufacturing the magnetron.

  The magnetron has an oscillation unit, an input unit, and an output unit. The oscillating unit includes an anode unit, a cathode unit, and a pair of pole pieces. The anode part has an anode cylinder and a plurality of vanes arranged inside the anode cylinder. The cathode portion has a filament disposed on the axis of the anode cylinder. The pair of pole pieces are disposed at both ends of the anode cylinder in the axial direction.

  The input unit has a stem that supports a cathode lead extending through one pole piece of the oscillation unit. The output unit has an antenna extending through the other pole piece. The pole piece is arranged so as to be sandwiched between permanent magnets, and concentrates the magnetic flux in the working space between the anode part and the cathode part.

  When a filament current is supplied from the input section to the cathode and a voltage is applied between the anode section and the cathode section, the magnetron oscillates in the microwave and outputs a microwave from the output section. In a general microwave magnetron, the oscillation frequency is 2450 MHz. Since a part of the oscillation output leaks from the input unit and becomes an obstacle to the external device, the input unit is shielded by a filter box, and radio wave leakage is suppressed. The oscillation output oscillates not only the fundamental wave of 2450 MHz but also a radio wave having a wide frequency band due to electronic disturbance or the like, and the filter box suppresses leakage of these radio waves.

  The filter box has a pair of feedthrough capacitors that are connected to an external power source and also serve as external input terminals. In the filter box, a pair of choke coils that connect the pair of cathode input stem terminals and the feedthrough capacitors in series are arranged.

JP-A-10-092693 JP 2007-122939 A

  A grounding plate is provided in the feedthrough capacitor that passes through the filter box. The feedthrough capacitor is fixed by pressing the ground plate around the through hole of the filter box. If there is a gap between the ground plate and the filter box, electromagnetic waves may leak from the gap and become a noise source for surrounding equipment.

  Therefore, an object of the present invention is to make it difficult to form a gap between the filter box of the magnetron and the ground plate of the feedthrough capacitor.

In order to solve the above-described problems, the present invention provides a magnetron main body having a cathode terminal, a conductive filter box having a side surface in which an opening is formed and covering the cathode terminal, and connected to the cathode terminal. And a choke coil housed in the filter box, a cylindrical body extending through the opening, and a conductive ground plate surrounding the body and extending perpendicularly to the axis of the body, and tapered portion is formed in the connecting portion between the body portion and the ground plate, the body portion being connected to the choke coil Rutotomoni, the ground plate so as to press against the tapered portion to the peripheral edge of said opening said filter box And a feedthrough capacitor fixed to the capacitor.

Further, the present invention provides a magnetron filter attached to a magnetron body having a cathode terminal, a conductive filter box having a side surface in which an opening is formed and covering the cathode terminal, and connected to the cathode terminal, A choke coil housed in a filter box; a cylinder extending through the opening; and a conductive ground plate surrounding the trunk and extending perpendicularly to the axis of the trunk; and the ground plate tapered portion is formed in the connecting portion between the body portion, the body portion being connected to the choke coil Rutotomoni, the ground plate so as to press against the tapered portion to the peripheral edge of the opening is fixed to the filter box And a feedthrough capacitor.

Further, the present invention provides a method for producing a magnetron, a step of forming a magnetron body having a cathode terminal, a step of forming a conductive filter box having a side surface in which an opening is formed and covering the cathode terminal, A step of accommodating a choke coil in the filter box and connecting the choke coil to the cathode terminal; a barrel extending in a cylindrical shape; and a conductive grounding plate surrounding the barrel and extending perpendicularly to the axis of the barrel; Forming a feedthrough capacitor having a tapered portion formed at a connection portion between the ground plate and the body portion; passing the feedthrough capacitor through the opening; and pressing the tapered portion against a periphery of the opening. a step of secure the base plate to the filter box, characterized by comprising the steps of connecting the feedthrough capacitor to said choke coil.

According to the present invention, when the peripheral edge of the opening is pushed by the tapered portion of the ground plate, the peripheral edge follows the tapered portion and is slightly deformed, so that a gap is formed between the filter box of the magnetron and the ground plate of the feedthrough capacitor. It becomes difficult.

It is a longitudinal cross-sectional view of one embodiment of the magnetron according to the present invention. It is a top view of the filter box vicinity in one Embodiment of the magnetron based on this invention. It is a partial side view of the filter box in one embodiment of the magnetron according to the present invention. It is an expanded sectional view of the connection part of the filter box and feedthrough capacitor in one embodiment of the magnetron according to the present invention.

  An embodiment of a magnetron according to the present invention will be described with reference to the drawings. This embodiment is merely an example, and the present invention is not limited to this.

  FIG. 1 is a longitudinal sectional view of an embodiment of a magnetron according to the present invention. FIG. 2 is a plan view of the vicinity of the filter box in the magnetron of the present embodiment. FIG. 3 is a side view of a part of the filter box in the magnetron of the present embodiment. FIG. 4 is an enlarged cross-sectional view of a connection portion between the filter box and the feedthrough capacitor in the magnetron of the present embodiment.

  This magnetron is used for a microwave oven, for example. The magnetron includes a magnetron main body and a filter box 31.

  The magnetron main body has an anode part and a cathode part. The anode part has an anode cylinder 12 and a plurality of vanes 13 protruding from the inner peripheral surface of the anode cylinder 12 toward the tube axis. The cathode portion has a filament 15, a pair of end hats 16, 17, a cathode center lead 18, and a cathode side lead 19. The filament 15 is disposed on the tube axis of the magnetron. The end hats 16 and 17 are provided at both ends of the filament 15 in the tube axis direction. The cathode center lead 18 and the cathode side lead 19 extend toward the input portion of the magnetron body. The cathode center lead 18 and the cathode side lead 19 are connected to both ends of the filament 15 via end hats 16 and 17, respectively.

  Between the free end of the vane 13 opposite to the anode cylinder 12 and the filament 15, the vane 13 is disposed so as to have a predetermined interval. The annular space having the predetermined interval becomes an action space 23.

  At both ends of the anode cylinder 12 in the tube axis direction, a pair of funnel-shaped (mortar-shaped) pole pieces 20 and 21 are provided so as to face each other with the working space 23 interposed therebetween. On the outer side in the tube axis direction of each of the pole pieces 20 and 21, an input unit for supplying a current for applying a filament and a high voltage for driving a magnetron, and an output unit including an antenna lead 41 for transmitting and radiating microwaves, Is provided. One end of the antenna lead 41 is connected to one vane 13. The other of the antenna leads 41 extends toward the output unit along the tube axis.

  A pair of annular permanent magnets 50 and 51 made of ferrite are provided on both outer sides in the tube axis direction of the pair of pole pieces 20 and 21. In addition, frame-shaped yokes 52 and 53 are provided so as to surround the outer sides and the side surfaces of the annular permanent magnets 50 and 51 in the tube axis direction. The frame-like yokes 52 and 53 are made of a ferromagnetic material. The annular permanent magnets 50, 51 are magnetically coupled to the pole pieces 20, 21 on the surface facing the pole pieces 20, 21 and to the frame-shaped yokes 52, 53 on the opposite surface of the pole pieces 20, 21, respectively. A magnetic field is supplied to the working space 23 between the vane 13 and the filament 15 by the constructed magnetic circuit.

  The filter box 31 covers the input part of the magnetron. The input unit includes a ceramic stem 32 that holds the cathode center lead 18 and the cathode side lead 19, and a pair of cathode terminals 33 connected to the cathode center lead 18 and the cathode side lead 19, respectively.

  The filter box 31 is formed of an iron plate, and a through hole 85 is formed on a side surface. Further, a caulking hole 75 pushed out from the outside to the inside is formed around the through hole 85. Further, a caulking hole 76 cut and raised from the outside to the inside is formed around the through hole 85.

  A two-terminal feedthrough capacitor 34 that passes through the side wall of the filter box 31 is attached. A choke coil 35 is connected in series between each of a pair of cathode terminals 33 located substantially in the center of the filter box and a terminal 81 inside the filter box 31 of the feedthrough capacitor 34. The feedthrough capacitor 34 and the choke coil 35 form a filter circuit.

  Each choke coil 35 is formed by connecting a core type inductor 36 and an air core type inductor 37 in series. The core type inductor 36 has a columnar magnetic core 91. The air core type inductor 37 side is connected to the cathode terminal 33 through a bent wire 38 having a predetermined length. The core type inductor 36 side is connected to the terminal 81 of the feedthrough capacitor 34. The external terminal 73 of the feedthrough capacitor 34 is connected to an external power source.

  The feedthrough capacitor 34 includes cylindrical body portions 71 and 77 and a ground plate 80. The cylindrical portion includes an inner body 71 and an outer body 77. The ground plate 80 is provided at a boundary portion between the inner body 71 and the outer body 77. The inner body 71 has a smaller cross section than the outer body 77.

  The ground plate 80 is an iron plate and surrounds the periphery of the body portions 71 and 77. The ground plate 80 has a tapered portion 78 and a flat plate portion 79. The tapered portion 78 is fixed to the body portions 71 and 77 at a boundary portion between the inner body portion 71 and the outer body portion 77. It is inclined with respect to the shafts of the body parts 71 and 77 and the flat part around the through hole 85 of the filter box 31. The flat plate portion 79 of the ground plate 80 extends perpendicularly to the axes of the trunk portions 71 and 77.

  The feedthrough capacitor 34 passes through the through hole 85 of the filter box 31. The feedthrough capacitor 34 is provided in the filter box 31 to crush the tip of a cylindrical caulking 72 that penetrates the flat plate portion 79 of the ground plate 80, and the flat caulking 74 is directed toward the flat plate portion 79 of the ground plate 80. The ground plate 80 is fixed by being bent and pressed against the filter box 31. The ground plate 80 and the filter box 31 are at ground potential.

  If there is a gap between the ground plate 80 of the feedthrough capacitor 34 and the filter box 31, electromagnetic waves may leak from the gap and affect the surroundings. When a ground plate having only a flat portion is used as a fixed portion to the filter box 31, a gap may be generated due to the ground plate or the distortion of the filter box 31. However, in the present embodiment, a tapered portion 78 is formed at the connection portion between the body portion 71 and 77 of the ground plate 80 of the feedthrough capacitor 34. For this reason, when the ground plate 80 is pressed and fixed to the filter box 31, somewhere in the tapered portion 78 easily comes into contact with the peripheral edge of the through hole 85 of the filter box 31. Further, by pressing the peripheral edge of the through-hole 85 by the tapered portion 78, the peripheral edge follows the tapered portion 78 and is slightly deformed, thereby making it difficult to form a gap.

  Thus, according to the present embodiment, it is difficult to form a gap between the ground plate of the feedthrough capacitor of the magnetron and the filter box.

12 ... anode cylinder, 13 ... vane, 15 ... filament, 16 ... end hat, 17 ... end hat, 18 ... cathode center lead, 19 ... cathode side lead, 20 ... pole piece, 21 ... pole piece, 23 ... working space, DESCRIPTION OF SYMBOLS 31 ... Filter box, 32 ... Ceramic stem, 33 ... Cathode terminal, 34 ... Feed-through capacitor, 35 ... Choke coil, 36 ... Core type inductor, 37 ... Air core type inductor, 38 ... Bending wiring, 41 ... Antenna lead, 50 ... Ring Permanent magnet, 51 ... annular permanent magnet, 52 ... frame yoke, 53 ... frame yoke, 71 ... body, 72 ... caulking, 74 ... caulking, 77 ... body, 78 ... taper, 79 ... flat plate, 80 ... Grounding plate, 81 ... Terminal, 85 ... Through hole, 91 ... Magnetic core

Claims (4)

A magnetron body having a cathode terminal;
A conductive filter box having a side surface in which an opening is formed and covering the cathode terminal;
A choke coil connected to the cathode terminal and housed in the filter box;
A cylindrical portion extending through the opening and a conductive grounding plate surrounding the barrel and extending perpendicularly to the axis of the barrel, and a tapered portion at a connection between the grounding plate and the barrel There is formed a through capacitor the barrel is connected to said choke coil Rutotomoni, the ground plate so as to press against the tapered portion to the peripheral edge of the opening is fixed to the filter box,
A magnetron comprising: The ground plate is disposed inside the filter box;
The magnetron according to claim 1 wherein the tapered portion, characterized in that is inclined in a direction away from the filter box of the filter box as an outer peripheral side from the center side of the ground plate. In the magnetron filter attached to the magnetron body having the cathode terminal,
A conductive filter box having a side surface in which an opening is formed and covering the cathode terminal;
A choke coil connected to the cathode terminal and housed in the filter box;
A cylindrical portion extending through the opening and a conductive grounding plate surrounding the barrel and extending perpendicularly to the axis of the barrel, and a tapered portion at a connection between the grounding plate and the barrel There is formed a through capacitor the barrel is connected to said choke coil Rutotomoni, the ground plate so as to press against the tapered portion to the peripheral edge of the opening is fixed to the filter box,
A filter for magnetron, comprising: Forming a magnetron body having a cathode terminal;
Forming a conductive filter box having a side surface in which an opening is formed and covering the cathode terminal;
Receiving a choke coil in the filter box and connecting to the cathode terminal;
A through-hole comprising a cylindrically extending body part and a conductive grounding plate surrounding the body part and extending perpendicularly to the axis of the body part, and having a tapered part formed at a connection part between the grounding plate and the body part Forming a capacitor;
A step of said through-capacitor passed through the opening to secure the said ground plate to the filter box while pressing the tapered portion to the peripheral edge of the opening,
Connecting the feedthrough capacitor to the choke coil;
A method for producing a magnetron, comprising:

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